A5074429925- Antenna Design and Analysis
- Microwave Engineering and Waveguides
- Advanced Antenna and Metasurface Technologies
- Antenna Design and Optimization
- Radio Astronomy Observations and Technology
- Microwave Imaging and Scattering Analysis
- Geophysical Methods and Applications
- Energy Harvesting in Wireless Networks
- Microwave and Dielectric Measurement Techniques
- Electromagnetic Simulation and Numerical Methods
- Electromagnetic Scattering and Analysis
- Indoor and Outdoor Localization Technologies
- Electromagnetic Compatibility and Measurements
- Ultrasonics and Acoustic Wave Propagation
- Radio Wave Propagation Studies
- Wireless Body Area Networks
- Advanced MIMO Systems Optimization
- Ultra-Wideband Communications Technology
- Astrophysics and Cosmic Phenomena
- Electromagnetic Compatibility and Noise Suppression
- Spacecraft Design and Technology
- Scientific Research and Discoveries
- Astronomical Observations and Instrumentation
- Advanced Frequency and Time Standards
- Social Media in Health Education
Chalmers University of Technology
2017
Dartmouth College
2017
Curtin University
2011-2015
International Centre for Radio Astronomy Research
2011-2015
Australian National University
2008-2011
The University of Queensland
1998-2007
Nanyang Technological University
2001-2005
Monash University
2005
Commonwealth Scientific and Industrial Research Organisation
2002-2004
University of Delhi
1999-2003
The design and development of a dual linearly polarized aperture coupled circular microstrip patch antenna at C-band are presented. uses novel configuration symmetric asymmetric coupling slots. Variations in isolation between orthogonal feedlines axial ratio with the position slots studied broadband achieved. prototype yields 7.6 dBi peak gain, 70/spl deg/ 3-dB beam width, 25 dB cross-polarization levels an better than 28 two ports. With external quadrature hybrid coupler connected to...
Abstract The redshifted 21cm line of neutral hydrogen ( Hi ), potentially observable at low radio frequencies (~50–200 MHz), should be a powerful probe the physical conditions inter-galactic medium during Cosmic Dawn and Epoch Reionisation (EoR). sky-averaged signal is expected to extremely weak (~100 mK) in comparison foreground up 10 4 K lowest interest. detection such requires an stable, well characterised system good understanding foregrounds. Development nearly perfectly (~mK accuracy)...
We report characterization results for an engineering prototype of a next-generation low-frequency radio astronomy array. This prototype, which we refer to as the Aperture Array Verification System 0.5 (AAVS0.5), is sparse pseudo-random array 16 log-periodic antennas designed 70-450 MHz. It co-located with Murchison Widefield (MWA) at Radioastronomy Observatory (MRO) near Australian Square Kilometre (SKA) core site. characterize AAVS0.5 using two methods: in-situ interferometry astronomical...
This paper offers an electromagnetic, more specifically array theory, perspective on understanding strong instrumental polarization effects for planar low-frequency "aperture arrays" with the Murchison Widefield Array (MWA) as example. A long-standing issue that has been seen here is significant Stokes leakage after calibration, particularly in Q at high frequencies. simple model accounts inter-element mutual coupling presented which explains prominence of when scanned away from zenith...
This letter describes an efficient three-dimensional (3D) image reconstruction algorithm for microwave tomography. Using the thin-wire approximation with resistive voltage sources (RVS), a realistic FDTD model is created transmitting and receiving antennas. To verify algorithm, made from experimental data using cylindrical test object of sunflower oil. In results, successful has been shown, indicating that applicable. For comparison, two-dimensional (2D) version was made. A significant...
The redshifted 21cm line of neutral hydrogen (Hi), potentially observable at low radio frequencies (~50-200 MHz), is a promising probe the physical conditions inter-galactic medium during Cosmic Dawn and Epoch Reionisation (EoR). sky-averaged Hi signal expected to be extremely weak (~100 mK) in comparison Galactic foreground emission (~$10^4$ K). Moreover, spectra measured by ground-based instruments are affected chromatic propagation effects (of order tens Kelvins) originating ionosphere....
This paper presents the design and development of a compact dual linearly polarized aperture coupled microstrip patch antenna array at S-band for RFID reader applications. The 2/spl times/2 uses two symmetric dog-bone shaped coupling aperture. prototype yields 14.6 dBi peak gain, 36/spl deg/ half-power beam width (HPBW) in both E H-planes, 28 dB cross-polarization levels an isolation better than 35 between polarization designed frequency bandwidth. These performances make very much suitable
This letter presents a detailed study of microwave tomography system using 3-D finite-difference time-domain methods (FDTDs). The algorithm, which uses subcell model in form the thin-wire approximation to wire antennas, has been validated numerically published numerical electromagnetic code (NEC) data for dipole and experimentally by comparing with measurements obtained monopole antenna array. agreement between calculated measured performances monopoles is close. In order understand...
Aperture Arrays (AA) mark a new era in radio astronomy combining high sensitivity with large field-of-view, enabling very survey and imaging speeds. This paper describes the development of low frequency aperture arrays leading up to SKA phase 1 within Array Verification Program (AAVP) as part program.
Abstract This paper presents the design and development of a compact dual linearly polarized aperture‐coupled microstrip patch antenna array system for radio frequency identifications (RFID) applications. Two different designs, Antenna‐1 Antenna‐2, RFID tag reader applications are presented at C S bands, respectively. The antennas use two symmetric coupling apertures to excite orthogonal modes dual‐polarization operation. High isolation order −35 dB is obtained by proper selection shape...
This article presents various novel and conventional planar electromagnetic bandgap (EBG)-assisted transmission lines. Both microstrip lines coplanar waveguides (CPWs) are designed with circular, rectangular, annular, plus-sign fractal-patterned EBGs dumbbell-shaped defected ground structure (DGS). The dispersion characteristics the slow-wave factors of design investigated. © 2006 Wiley Periodicals, Inc. Int J RF Microwave CAE, 2006.
This paper describes an approach to model the impulse response of a dielectric target below half‐space using time domain deconvolution technique. The complex natural resonances (CNR) are extracted from matrix pencil method and can be correlated with target's physical properties. An automated E‐pulse scheme has been used discriminate changes in properties target. discrimination performance is calculated quantitatively by energy number (EDN) ratio (DR). technique ultimately as diagnostic tool...
This paper presents an in-depth investigation into the design parameters of a microstrip Yagi antenna for possible use in indoor wireless LAN system. The investigated uses aperture coupling feeding mechanism and can be placed horizontal plane to communicate with base station. variations return loss gain as function various dimensions this are studied aid full-wave electromagnetic field analysis tool obtain optimal performance.
Progress in microwave and millimeter-wave technologies has made possible advanced diagnostics for application to various fields, such as, plasma diagnostics, radio astronomy, alien substance detection, airborne spaceborne imaging radars called as synthetic aperture radars, living body measurements. Transmission, reflection, scattering, radiation processes of electromagnetic waves are utilized diagnostic tools. In this report we focus on the reflectometric measurements applications biological...
The complex design and development of a planar multilayer phased array antenna in microstrip technology can be simplified using two commercially available tools (1) Ansoft Ensemble (2) HP-EEsof Touchstone. In the approach presented here, Touchstone is used to RF switches phase shifters whose scattering parameters are incorporated simulations its black box tool. Using this approach, able analyze fully performance radiating beamforming layers prior manufacture. This strategy demonstrated...
Accurate, computationally intensive numerical algorithms have become necessary to handle the increasing complexity of electromagnetic problems in biological applications. In this work, a high performance hybrid - MoM/FDTD approach is presented for analysis and design applications microwave breast tumor detection. The proposed algorithm based on Huygen's equivalent surface methods. simulation study bow-tie antenna-breast phantom interaction demonstrates efficacy suggests that, with further...
Nonlinear microwave imaging heavily relies on an accurate numerical electromagnetic model of the antenna system. The is used to simulate scattering data that compared its measured counterpart in order reconstruct image. In this paper system immersed water image different canonical objects investigate implication modeling errors final reconstruction using a time domain-based iterative inverse algorithm and three-dimensional FDTD modeling. With test background air tap water, respectively, we...
We present an in-situ antenna characterization method and results for a "low-frequency" radio astronomy engineering prototype array, characterized over the 75-300 MHz frequency range. The presence of multiple cosmic sources, particularly dominant Galactic noise, makes at these frequencies challenging; however, it will be shown that high quality measurement is possible via interferometry techniques. This well-known in community but seems less so wireless communications communities, although...
This paper presents a comprehensive parametric study of an inductively coupled CPW fed slot dipole antenna on GaAs substrate for MMIC applications. The includes return loss, impedance bandwidth, broadside gain, radiation pattern and front to back (F/B) ratio. It is observed that given dimensions, the feed inset tremendously changes both resonant frequency input match. Calculated measured RL gain patterns are compared at 24 GHz ISM band. manufactured resonates 22.4 with 6.1% bandwidth 84/spl...
The paper presents the design of a miniaturized slot ring antenna for RFID applications. In order to obtain an reduced size, Minkowski fractal island shaping is applied. presented design, 40% size reduction obtained using second iteration. Calculated and measured results first two iterations are given. performance developed antennas shows high potential applications, where small RF tag system key importance.
Design and development of a dual polarized aperture coupled circular microstrip patch antenna at C-band are presented. Two orthogonal feeds exciting the yield greater than 28 dB isolation. The has 7.8 dBi gain, 70/spl deg/ 3-dB beamwidth 7 front-to-back ratio. These features make very suitable for medium range radio frequency automatic identification (RFID) applications.
The paper reports an investigation into various designs of printed planar monopole antennas for UWB applications. Three different (designated Ant I, II and III) have been chosen investigated. I uses a straight feed line, while III use tapered line. taper length angle optimized with HFSS. III, the section, exhibit wider bandwidth. calculated radiation patterns are omnidirectional in horizontal plane at 3.0 GHz 7 GHz. However, higher frequencies they more ripple. results indicate that suitable...
This paper presents the performance of a non-uniform annular ring patterned PBG assisted transmission line. The radii rings are selected based on Tchebyscheff polynomial. Based approximation, line is simulated IE3D and prototype lines built tested. Both measured S-parameters exhibit significant improvement in ripple height rejection bandwidth over conventional microstrip lines.